Development of New Evaluation Method for Adhesive Strength between Microsized Photoresist and Si Substrate of MEMS Devices
An evaluation method for adhesive bending and shear strengths between microsized components and silicon substrate were developed to quantitively determine micro-sized adhesive strength for micro-electro mechanical system (MEMS) devices. Cylindrical shape is employed as a micro-sized adhesive specimen to simply analyze adhesive stresses of both shear and bending. Micro-sized adhesive tests between micro-sized SU-8 cylindrical specimen and Si substrate were performed using a mechamical testing machine for micro-sized material that has developed by our group. Delamination of all the specimens occurred within the SU-8 near by the substrate in a brittle manner under both bending and shear loading conditions. The adhesive bending stress is 57 % lower than the bend strength of the SU-8 material. The adhesive shear strength under bend loading is 15 % lower than the adhesive strength under shear loading and the delamination surface is different in each loading mode. All the results suggest that some defects at the interface must induce the stress concentration, which may make the apparent strength of SU-8 decrease.
S.W. Nam, Y.W. Chang, S.B. Lee and N.J. Kim
C. Ishiyama et al., "Development of New Evaluation Method for Adhesive Strength between Microsized Photoresist and Si Substrate of MEMS Devices ", Key Engineering Materials, Vols. 345-346, pp. 1185-1188, 2007